Measuring and comparator device



Aug. 13, 1968 R. D. BRACKETT MEASURING AND COMPARATOR DEVICE Filed Sept. l, 1966 Ul a INVENTOR. MMI 9. @new ATTORNEYS United States Patent Oiiice 3,396,577 Patented Aug. 13, 1968 3,396,577 MEASURING AND COMPARA'IORv DEVICE Robert D. Brackett, Wakefield, Mass., assignor to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware Filed Sept. 1, 1966, Ser. No. 576,660 10 Claims. (Cl. 73-141) This invention relates to a novel testing or comparator device for determining the compressive characteristics of adjustably mounted pressure rolls and for enabling the correction of compressive settings of the rolls with respect to given materials introduced therebetween.

Where rotatable pressure rolls having resilient surfaces are utilized for applying a compressive and/or propulsive force for some given purpose to sheet materialspassed therebetween, it is generally necessary to insure that the dynamic pressure exerted by the aforesaid roll surfaces is correct. It is also of importance to make certain that the rolls are capable of providing a consistent compressive force throughout their surfaces, that is, that no ilaws in the surfacing sheaths of the rolls or other causes of uneven compressive function shall exist.

Instances of usage in which the aforementioned considerations are of significance include laminating procedures wherein two or more sheet materials having adjacent surfaces adapted to be bonded together or having a bonding substance introduced therebetween are subjected to compression between one or more pairs of rotatable pressure rolls, each roll, for example having a sheath or casing of a natural or synthetic resilient or elastic material. The above-mentioned factors are also of importance in the printing art as, for example, with respect to rolls employed in offset printing processes.

A particular contemplated type of pressure roll is that which may be employed in the photographic field for some especially exacting purpose requiring the bringing together and compression of delicate film surfaces. One such purpose involves the processing of photosensitive film materials wherein, after a photographic exposure, a processing liquid is released and spread between the layers of a composite film structure to effect a diffusion transfer of imageforming substances and the production of a photographic print on one of the layers. To obtain a correct spreading and thickness of the processing liquid and the production of a perfect print, a measurement of correct dynamic pressure and a determination of the presence or absence of imperfections in the roll surfacing material are of extreme importance. While pressure rolls having a non-yielding surface, e.g., metallic pressure rolls, are predominantly employed in the foregoing diffusion-transfer process, at least in the instance where they are incorporated in handheld cameras of the type sold by Polaroid Corporation of Cambridge, Massachusetts, U.S.A., in other examples such as that wherein the pressure rolls are components of an X-ray hlm-processing device, also sold by Polaroid Corporation, they may, appropriately, be resiliently surfaced, as described hereinbefore, and may be employed both for compressive and propulsive functions associated with the release and spreading of a liquid for a processing purpose, as well as for the removal of a processed film assembly from an enclosing chamber or the like.

In view of the foregoing considerations, objects of the invention are to provide a device which may be termed a comparator for readily obtaining an indication or reading of the dynamic-pressure characteristics of a pair of rotatable, cooperating pressure rolls and for enabling an adjustment of said characteristics according to said indication; to provide a device for revealing possible imperfections within a resilient functional surfacing material or sheath of the pressure rolls; to provide a device of the character described which gives both a dynamic-pressure reading and a reading of any compression fluctuations which may occur at different surface portions of the pressure rolls due, for example, to material imperfections or faulty rotational characteristics; to provide a device of the category stated wherein a first dynamic pressure reading is monitored for accuracy by a second compression-characteristic reading; to provide a device of the character described having a scale calibrated in one of a choice of possible indicia comprising roll durometer values; metering speed of materials compressed; resiliency of materials compressed, etc. and to provide a device or gauge of the type characterized which is of simple construction, inexpensive, highly accurate, and adapted to use in the field without requiring any dismantling of apparatus to be adiusted, thus permitting measurements to be taken with utmost ease and rapidity.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the apparatus possessing the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing wherein:

FIGURE l is a diagrammatic plan view of the testing device or gauge of the present invention;

FIG. 2 is a diagrammatic, sectional elevation view of the device, taken along the line 2-2 of FIGURE 1; and

FIG. 3 is a diagrammatic end view, partly in section, taken along the line 3 3 of FIGURE 1.

Referring now to FIGURE l, the device 10 of the invention is shown from above. It includes a central element or support 12, namely, a relatively thin elongated strip of a metal, a plastic or the like having a tapered slot 14 and a rectangular slot 16 formed therein. The slots 14 and 16 extend in sde-by-side relation longitudinally of the element 12, their axes being parallel. Two strips or tapes of similar dimensions, namely, an upper tape 18 and a lower or underlying tape 20, composed of a flexible material, preferably light-transmitting, each having an adhesive 22 coated on an inner or facing surface, are attached by means of the adhesive surfaces to opposite sides of the central element 12. The tapeslS and 20 are aligned with one another and are of a width and length sufficient to cover the slots 14 and 16 and adhere firmly to the element 12 in areas surrounding the slots. The slots 14 and 16 include transversely extending air-venting portions 14a and 16a, respectively, which protrude laterally slightly beyond the edges of the superimposed tapes 18 and 20. The tapered slot 14` is marked off along its length by indicia representative of various hardness values associated with a durometer. The assembly of FIGURE 1 is adapted to be passed between a pair of resiliently surfaced, rotatable pressure rolls for the purpose of determining or measuring the dynamic pressure exerted thereby and the presence, of or freedom from, defects or blemishes on or within the roll surfaces.

FIG. 2, which is a sectional view taken along the line 2 2 of FIGURE l, longitudinally bisects the tapered slot 14 and illustrates the operation of the gauge with respect to a pair of rotatable pressure rolls 24 and 26 having, for example, steel cores 24a and 26a, and resilient sheaths 24b and 26h, respectively. It is to he assumed that the rolls 24 and 26 are mounted for rotation in bearing means which are positionable to permit relatively convergent or divergent translational movement of the rolls toward or away from one another. The convergent movement may be in the form of a biasing force instigated by spring means or the like, not shown. The rolls may also include either manual or power means such as a hand-crank or am motor, not shown, for providing their rotation, in which case they serve both a compressive and a propulsive function. Alternatively, rotation of the rolls .may be effected by drawing upon the device 10, frictional contact of the tapes 18 and 20 with the roll surfaces being suicient to effect their turning. The sheaths 24b and 26b may, appropriately, both be composed of a similar resilient material, e.g., a suitable rubber or a synthetic rubber such asfne'oprene, sold by E. I. du Pont de Nemours & Co., Inc., W11- mington, Del., U.S.A.

Further referring to FIGURE 1, the index marks 30, 40 and 50 relate to certain hardness values or indicia ofa durometer. The range of the indicia illustrated has been chosen with respect to commercially available pressure rolls having a durometer value lying within this range, For pressure rolls having other hardness or resilience characteristics, a different range of values would, of course, be employed. It is to be assumed that the testing device is undergoing relative movement with respect to the pressure rolls 24 and 26 in the direction indicated by the arrow 28 as, for example, by powered rotation of the rolls. It will thus be understood that a dynamic compressive force has been applied by the rolls such that the device 10 has undergone compression, extending from the right-hand extremity thereof to the portion which is shown positioned between the pressure rolls, and that compression is continuing in a direction toward the lefthand extremity. While a given direction of compression is illustrated, it is to be understood that this direction may, alternatively, be from left-to-right and that the latter direction may even be preferred. If this is the case, venting means similar to 14a and 16a would be included at the right-hand extremities of the slots 14 and 16.

The durometer data associated with pressure rolls are conventionally supplied therewith by the manufacturer. Assuming the surface material of the pressure rolls ernployed to lie within the durometer range of values illustrated, a given overall thickness of the device 10, and a given depth of the slot 14, then the width of the slot 14 at the portion 14b iirst introduced between the pressure rolls, is so chosen that the pressure roll surfaces 24b and 26b readily deform and are pressed into the slot depression from opposite sides to a functional depth. This causes the resilient tapes 18 and 20, against which the pressure roll surfaces bear, to corne into contact with one another and, by reason of the adhesive coating on their facing surfaces, to adhere to one another. The deformation characteristics of the roll surfaces, when taken with the given depth and given narrowing dimensions or taper angle of the slot 14, are such as to provide a tapering adhesion pattern 30 of the pressed-together tapes, terminating at a given point 30a longitudinally of the slot. This point is reached at a certain Width of the tapered slot 14 which is so narrow that, just beyond it to the left, the roll surfaces 24b and 26b cannot deform to that degree which is necessary to permit them to enter the slot and press the tapes 18 and 20 together. Continued relative movement of the device 10 and the pressure rolls in the direction indicated by arrow 28 will, of course, provide no extension to the left of the pattern 30. The venting portion 14a permits an expulsion of air from the slot which might otherwise build up to an unwanted pressure tending to operate against contact of the tape surfaces and leading to an incorrect establishment of the point 30a.

If, following the above-described procedures the point 30a of the test or comparator pattern is established opposite the index mark representing the known durometer value of the pressure rolls employed, it is to be assumed that the dynamic pressure exerted by the rolls will be correct with respect to the sheet material which is to undergo compression. If the point is at some other-index mark, the pressure rolls must be adjusted with respect to their relative contguity or spacing or their convergent bias to provide a correction of compressive force. After earch suchpdjustmentof the pressure rolls, the device 10 is passed between the rolls. When the adjustment is correct, the point 30a of the test pattern will lie opposite the known durometer index mark relating to the pressure rolls utilized. This position establishes arpredeterminedly correct dynamic compressive force exerted by the pressure rolls'with respect to a sheet material passed therebetween. The compressive operation is illustrated transversely of the device 10 in FIG. 3. v

The slot 16 serves adual purpose.- It monitors the reading Within the slotV 14 to a certain extent by indicating in the test pattern 32, again produced by a linear adhesion of 'the tapes V18 and 20 under compression, whether an evenness o r unevenness of pressure exists lengthwise of the rolls'along. a. line intersecting the point 30a. It also indicates byuneven pressure marks 32a any defects in the roll surfaces which may be suiciently serious to warrant replacement .of a defective roll. The venting portion 16a Serves a purpose similar to that of the vent 14a, above described.

The lengths of the slots 14 and 16 should be at least equal to the circumference of a pressure roll t'o give an adequate representation of the roll surfaces in terms of the test patterns. If the slots are of greater length, repeat test patterns may, advantageously, be produced. Certain dimensions of the device 10, satisfying the requirements of a workable testing device but t o be taken merely by way of example, involve a thickness of plate 12 of .020 inch; a slot length of 9 inches; a width of slot 14 at one end of 11/32 inch and of 1%@ inch at the other end; a width of slot .16` of 5/16 inch; and a taper of slot 14 of 1. The tapes 18 and 20 may, appropriately, both be a transparent Scotch tape, No. 600, sold by Minnesota Mining and Manufacturing Co., St. Paul, Minn., U.S.A. Alternatively one opaque and one clear tape, configurated metallic tapes or some other type thereof may be employed for forming the visibletest pattern, any such material being considered as falling within the scope of the invention.

The scale shown in FIGURE 1 may be calibrated in terms of indicia other than those shown to enlarge the field of usage y'of the device 10. Such alternative indicia are to be obtained from test runs involving pressure rolls of given characteristics and/ or sheet materials of given structure.Thus, for example, the scale may represent various thicknesses of sheet materialsv to be compressed with values, starting at the right and proceeding to the left, of .020", .015", .010" and .005". Another possible scale may comprise pounds-force values, with respect to compression of a given sheet material, e.g., 8 lbs., 10 lbs., 12 lbs., and 14 lbs., similarly arranged. A still further scale can be calibrated in terms of speed of movement of a sheet material between the pressure rolls, for example, from rightto-left, in Avalues of 90 ft., 75 ft., 60 ft., and 45 ft. per minute. Another type of scale can be calibrated, for instance, in values of resiliency of compressible sheet materials. In` each instance, it will be understood that a reading is taken by passing the Adevice between the pressure rolls, as previously described, observing the position of the test pattern point 30a, and adjusting the pressure roll compression kto'bring the point 30a to the desired or relevant index mar It is to be understood that the device 10 can be modified to an extent such that the plate 12 may include but one of the slots 14 and 16 and still retain one of the several functions attributed to they device as shown. Thus, for example, the slot 14, alone, provides the measuring or comparator function enabling corrective adjustment of the pressure rolls and the slot 16 alone permits a reading of roll surfacing defects, only the monitoring function being lost.

Since certain changes may be made in the above apparatus without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is: v

1. An element for use with a pair of resilient adhesive tapes for measuring and permitting adjustment of the dynamic compressive force exerted by a pair of pressure rolls having deformable surfaces, comprising an elongated, thin, generally rectangular, plate-like support component of a given thickness, an elongated slot of given length and width characteristics formed in said plate-like support element so as to extend longitudinally thereof throughout a distance which is at least equal to the circumference of one of said pressure rolls, and a scale comprising a plurality of index marks positioned along said elongated slots relating to the compression of a sheet material to be passed between said pressure rolls, said support component being adapted to have said tapes so aliixed to each of its opposite surfaces, in generally aligned relation, as to cover both sides of said elongated slot, said element, when passed endwise between said pressure rolls, deriving therefrom a mutual progressive adhesion of said tapes within a given limited area of said elongated slot, thus forming a test pattern in said tape which is determined as to its length, width and configuration by the width and depth characteristics of said slot, by the surface characteristics of said pressure rolls, and by the dynamic compressive force exerted by said pressure rolls, said test pattern being readable in terms of the indicia of said scale and relating to said dynamic compressive force.

2. An element for use with a pair of resilient adhesive tapes for measuring and permitting adjustment of the dynamic compressive force exerted by a pair of pressure rolls having deformable surfaces, comprising an elongated, thin, generally rectangular, plate-like support component of a given thickness, an elongated slot of given length and width characteristics formed in said plate-like support element so as to extend longitudinally thereof throughout a distance which is at least equal to the circumference of one of said pressure rolls, a scale comprising a plurality of index marks positioned along said elongated slot relating to the compression of a sheet material to be passed between said pressure rolls, and a relatively short, transverse air-venting slot formed in said support component and leading laterally from said elongated slot at at least one end of the latter, said support component being adapted to have said tapes so affixed to each of its opposite surfaces, in generally aligned relation, as to cover both sides of said elongated slot and to partially cover said transverse slot, said element, when passed endwise between said pressure rolls, deriving therefrom a mutual progressive adhesion of said tapes within a given limited area of said elongated slot, thus forming a test pattern therewithin which is determined as to its length, width and configuration by the width and depth characteristics of said slot, by the surface characteristics of said pressure rolls, and by the dynamic compressive force exerted rby said pressure rolls, said test pattern being readable in terms of the indicia of said scale and relating to said dynamic compressive force.

3. An element, as defined in claim 2, wherein said elongated slot is tapered to a given degree such that said deformable pressure-roll surfaces are capable of entering said slot to a functional depth at given widths of said slot when taken with a given dynamic compressive force exerted by said pressure rolls, but are incapable of entering said slot to said depth at other widths thereof and during other dynamic compressive forces exerted by said pressure rolls.

4. A comparator device for measuring the compressive characteristics of and permitting adjustment of the dynamic compressive force exerted by a pair of axially adjustable pressure rolls having deformable surfaces, said device comprising an elongated, thin, generally rectangular, plate-like support component of a given thickness, an elongated slot of given length and width characteristics formed in said plate-like support element so as to extend longitudinally thereof throughout a distance which is at least equal to the circumference of one of said pressure rolls, a scale comprising a plurality of index marks positioned along said elongated slot relating to the compression of a sheet material to be passed between said pressure rolls, a relatively short, transverse air-venting slot formed in said support component and leading laterally from said elongated slot at at least one end of the latter, and a pair of elongated resilient adhesive tape components so aiiixed in generally aligned relation to opposite surfaces of said support component as to cornpletely cover both sides of said elongated slot and to partially cover said transverse slot, said device, when passed endwise between said pressure rolls, deriving therefrom a mutual progressive adhesion of said tape components within a given limited area of said elongated slot, thus forming a test pattern in said tape components which is determined as to its length, width and conguration by the width and depth characteristics of said slot, by the surface characteristics of said pressure rolls, and by the dynamic compressive force exerted by said pressure rolls, said test pattern being readable in terms of the indicia of said scale and relating to said dynamic compressive force.

S. A comparator device for measuring the compressive characteristics of and adjustment of the dynamic compressive force exerted by a pair of axially adjustable pressure rolls having deformable surfaces, said device comprising an elongated, thin, generally rectangular, plate-like support component of a given thickness, a first elongated slot of given length and width characteristics and tapered to a given degree formed in said plate-like support element so as to extend longitudinally thereof, a second elongated non-tapered slot of given length and width characteristics formed in said plate-like support so as to extend longitudinally thereof in side-by-side relation to said first slot, both said slots extending throughout a distance which is at least equal to the circumference of one of said pressure rolls, a scale comprising a plurality of index marks relating to the compression of a sheet material to be passed between said pressure rolls, said scale being positioned along said tapered elongated slot, a pair of relatively short, transverse air-venting slots formed in said support component and leading laterally from said elongated slots at at least one end of each of the latter, and a pair of elongated resilient adhesive tape components so affixed in generally aligned relation to opposite surfaces of said support component as to cover both sides of said elongated slots and to partially cover said transverse slots, said device when passed endwise between said pressure rolls deriving therefrom a mutual progressive adhesion of said tape cornponents within a given limited area of said elongated slots, thus forming test patterns in said tape components which are determined as to configuration by the width and depth characteristics of said slots, by the surface characteristics of said pressure rolls, and by the dynamic compressive force exerted by said pressure rolls, said test pattern being readable in terms of the indicia of said scale and relating to said dynamic compressive force.

6. A device, as defined in claim 5, wherein at least one of said tape components is light transmitting.

7. A device, as defined in claim 5, wherein said scale relating to said tapered slot is calibrated in durometer indicia which includes a durometer value associated with the surfaces of said pressure rolls.

8. A device, as defined in claim 5, wherein said scale relating to said tapered slot is calibrated in terms of thicknesses of sheet materials to be passed between said pressure rolls.

7 8 9. A device, as deued in claim 5, wherein said scale References Cited relating to said tapered slot is calibrated in terms 0f FOREIGN PATENTS pounds force exerted by said pressure rolls.

10. AV device, as dened in claim 5, wherein said non- 101350 4/1911 Great Entamtapered slot exhibits, in terms of one of said test patterns, 5 RICHARD C QUEISSER Pfl-mmv Examiner the presence of absence of imperfect compressive action of said pressure rolls. CHARLES A. RUEHL, Asszstant Exqminer. 

1. AN ELEMENT FOR USE WITH A PAIR OF RESILIENT ADHESIVE TAPES FOR MEASURING AND PERMITTING ADJUSTMENT OF THE DYNAMIC COMPRESSIVE FORCE EXERTED BY A PAIR OF PRESSURE ROLLS HAVING DEFORMABLE SURFACES, COMPRISING AN ELONGATED, THIN, GENERALLY RECTANGULAR, PLATE-LIKE SUPPORT COMPONENT OF A GIVEN THICKNESS, AN ELONGATED SLOT OF GIVEN LENGTH AND WIDTH CHARACTERISTICS FORMED IN SAID PLATE-LIKE SUPPORT ELEMENT SO AS TO EXTEND LONGITUDINALLY THEREOF THROUGHOUT A DISTANCE WHICH IS AT LEAST EQUAL TO THE CIRCUMFERENCE OF ONE OF SAID PRESSURE ROLLS, AND A SCALE COMPRISING A PLURALITY OF INDEX MARKS POSITIONED ALONG SAID ELONGATED SLOTS RELATING TO THE COMPRESSION OF A SHEET MATERIAL TO BE PASSED BETWEEN SAID PRESSURE ROLLS, SAID SUPPORT COMPONENT BEING ADAPTED TO HAVE SAID TAPES SO AFFIXED TO EACH OF ITS OPPOSITE SURFACES, IN GENERALLY ALIGNED RELATION, AS TO COVER BOTH SIDES OF SAID ELONGATED SLOT, SAID ELEMENT, WHEN PASSED ENDWISE BETWEEN SAID PRESSURE ROLLS, DERIVING THEREFROM A MUTUAL PROGRESSIVE ADHESION OF SAID TAPES WITHIN A GIVEN LIMITED AREA OF SAID ELONGATED SLOT, THUS FORMING A TEST PATTERN IN SAID TAPE WHICH IS DETERMINED AS TO ITS LENGTH, WIDTH AND CONFIGURATION BY THE WIDTH AND DEPTH CHARACTERISTICS OF SAID SLOT, BY THE SURFACE CHARACTERISTICS OF SAID PRESSURE ROLLS, AND BY THE DYNAMIC COMPRESSIVE FORCE EXERTED BY SAID PRESSURE ROLLS, SAID TEST PATTERN BEING READABLE IN TERMS OF THE INDICIA OF SAID SCALE AND RELATING TO SAID DYNAMIC COMPRESSIVE FORCE. 